I would take the 420SEL
on the vacation and enjoy the ride then get it taken care of when I returned. If the oil has been changed often up to 80k miles then it should be fine. It is my opinion that the care given to a car the first 100k miles determines really how long the car will go. I had a 1986.5 Nissan 4 cyl pickup truck that I changed the oil at every 3k miles and sold at around 65k. I saw it the other day and it is now showing over 280k miles and I know they have never touched the timing chain.